Field of the Disclosure
This disclosure relates to a purge apparatus which carries out a purge process for a purge object vessel having a purge object space and a load port which includes a purge apparatus. More specifically, the present disclosure relates to a load port provided adjacent a semiconductor fabrication apparatus in a clean room and a purge apparatus which can be applied to a purge station or the like.
Description of the Related Art
In a fabrication process of semiconductors, processing of a wafer is carried out in a clean room to assure a high yield and high quality. However, in this day of highly integrated devices, miniaturized circuitry and wafers of increased sizes, it is difficult in terms of cost and technology to manage fine dust in an entire clean room. Therefore, in recent years, means configured to carry out transport and other processes of wafers employing a “minienvironment system” which improves the cleanness only of a local space around a wafer is adopted as a method which replaces the cleanness improvement of an entire clean room. In the minienvironment system, a containment called FOUP (Front-Opening Unified Pod) for transporting and storing a wafer in a highly clean environment and a load port which is an interface section for transferring a wafer from within the FOUP into a semiconductor fabrication apparatus or from the semiconductor fabrication apparatus into the FOUP and carrying out transfer of a FOUP to and from a transport apparatus are utilized as important apparatus. In particular, while the inside of the clean room, particularly the inside of the FOUP and the inside of the semiconductor fabrication apparatus, are kept in high cleanness, the space in which the load port is disposed, or in other words, the outside of the FOUP and the outside of the semiconductor fabrication apparatus, are allowed to be in low cleanness so that the construction and operating costs of the clean room are suppressed. Here, the FOUP has a loading entrance for a wafer on the front thereof and includes a door which can close up the loading entrance.
Thus, in a state in which a door section provided on the load port is kept in close contact with the door provided on the front of the FOUP, the door section and the door are opened simultaneously. Then, a wafer in the FOUP is supplied through the loading entrance into the semiconductor fabrication apparatus. Thereafter, the wafer for which various kinds of processing or working have been carried out is accommodated back into the FOUP from within the semiconductor fabrication apparatus.
Incidentally, while the inside of the semiconductor fabrication apparatus is maintained in a predetermined gas atmosphere suitable for processing or working of a wafer, when a wafer is to be forwarded from within the FOUP into the semiconductor fabrication apparatus, the internal space of the FOUP and the internal space of the semiconductor fabrication apparatus are placed into a mutually communicated state. Accordingly, if the environment in the FOUP is lower in cleanness than that in the inside of the semiconductor fabrication apparatus, then the gas in the FOUP may advance into the semiconductor fabrication apparatus and have a bad influence on the gas atmosphere in the semiconductor fabrication apparatus. On the other hand, when a wafer is to be accommodated into the FOUP from within the semiconductor fabrication apparatus, an oxide film may possibly be formed on the surface of the wafer by water, oxygen or some other gas in the gas atmosphere in the FOUP.
As a technique for coping with such problems as described above, a load port is disclosed in Japanese Patent Laid-Open No. 2009-038074. The load port includes a purge apparatus which blows predetermined gas such as, for example, nitrogen or inert gas into the FOUP by a purge section or purge nozzle provided on the semiconductor fabrication apparatus side with respect to the opening in a state in which the internal space of the FOUP and the internal space of the semiconductor fabrication apparatus are communicated with each other with the door of the FOUP opened by the door section of the load port.
However, according to such a purge apparatus of the front purge type which injects predetermined gas into the FOUP from the front side, that is, from the semiconductor fabrication apparatus side, into the FOUP opened to the inner space of the semiconductor fabrication apparatus through the loading entrance to place the inside of the FOUP into a predetermined gas atmosphere, a purge process is carried out in a state in which the opening of the FOUP is opened so that the internal space of the FOUP is directly communicated with the entire internal space of the semiconductor fabrication apparatus. Therefore, the purge apparatus has a disadvantage that it is difficult to keep the inside of the FOUP in a high predetermined gas atmosphere concentration and the reaching concentration of the predetermined gas atmosphere is low.
Meanwhile, Japanese Patent Laid-Open No. 2006-351619 discloses a load port which includes a purge apparatus which injects, when it is detected that a FOUP in which a wafer is accommodated is placed on a receiving table of the load port, predetermined gas such as nitrogen or inert gas into the FOUP from the bottom face side of the FOUP to fill the FOUP to place the inside of the FOUP into a predetermined gas atmosphere. Such a purge apparatus of the bottom purge type which injects gas such as nitrogen or dry air into the FOUP from the bottom face side of the FOUP to place the inside of the FOUP into a predetermined gas atmosphere as just described is advantageous in that the reaching concentration of the predetermined gas atmosphere is high in comparison with the purge apparatus of the front purge type.